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001-es BibID:	BIBFORM065104
035-os BibID:	(WoS)000380371400013 (Scopus)84993661764
Első szerző:	Mocsár Gábor (biofizikus)
Cím:	MHC I expression regulates co-clustering and mobility of interleukin-2 and -15 receptors in T cells / G. Mocsár, J. Volkó, D. Rönnlund, J. Widengren, P. Nagy, J. Szöllősi, K. Tóth, C. K. Goldman, S. Damjanovich, T. A. Waldmann, A. Bodnár, G. Vámosi
Dátum:	2016
ISSN:	0006-3495
Megjegyzések:	MHC glycoproteins form supramolecular clusters with interleukin-2 and -15 receptors in lipid rafts of T cells.The role of highly expressed MHC I in maintaining these clusters is unknown. We knocked down MHC I inFT7.10 human T cells, and studied protein clustering at two hierarchic levels: molecular aggregations andmobility by FRET and fluorescence correlation spectroscopy, and segregation into larger domains orsuperclusters by superresolution STED microscopy. FCS based molecular brightness analysis revealed thatthe studied molecules diffused as tight aggregates of several proteins of a kind. Knockdown reduced thenumber of MHC I containing molecular aggregates and their average MHC I content, and decreased theheteroassociation of MHC I with IL-2R?/IL-15R?. The mobility of not only MHC I but also that of IL-2R?/IL-15R? increased, corroborating the general size decrease of tight aggregates. A multifaceted analysis of STEDimages revealed that the diameter of MHC I superclusters diminished from 400-600 to 200-300 nm, whereasthose of IL-2R?/IL-15R? hardly changed. MHC I and IL-2R?/IL-15R? colocalized with GM1 gangliosiderichlipid rafts, but MHC I clusters retracted to smaller subsets of GM1- and IL-2R?/IL-15R?-rich areas uponknockdown. Our results prove that changes in expression level may significantly alter the organization andmobility of interacting membrane proteins.
Tárgyszavak:	Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban folyóiratcikk
Megjelenés:	Biophysical Journal. - 111 : 1 (2016), p. 100-112. -
További szerzők:	Volkó Julianna (1983-) (biotechnológus) Rönnlund, Daniel Widengren, Jerker Nagy Péter (1971-) (biofizikus) Szöllősi János (1953-) (biofizikus) Tóth Katalin (Heidelberg) Goldman, Caroline K. Damjanovich Sándor (1936-2017) (biofizikus) Waldmann, Thomas A. Dóczy-Bodnár Andrea (1970-) (biofizikus) Vámosi György (1967-) (biofizikus)
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001-es BibID:	BIBFORM060655
Első szerző:	Szalóki Nikoletta (biológus)
Cím:	Evidence for Homodimerization of the c-Fos Transcription Factor in Live Cells Revealed by Fluorescence Microscopy and Computer Modeling / Nikoletta Szalóki, Jan Wolfgang Krieger, István Komáromi, Katalin Tóth, György Vámosi
Dátum:	2015
ISSN:	0270-7306
Megjegyzések:	The c-Fos and c-Jun transcription factors, members of the activator protein 1 (AP-1) complex, form heterodimers and bind to DNA via a basic leucine zipper and regulate the cell cycle, apoptosis, differentiation, etc. Purified c-Jun leucine zipper fragments could also form stable homodimers, whereas c-Fos leucine zipper homodimers were found to be much less stable in earlier in vitro studies. The importance of c-Fos overexpression in tumors and the controversy in the literature concerning c-Fos homodimerization prompted us to investigate Fos homodimerization. Förster resonance energy transfer (FRET) and molecular brightness analysis of fluorescence correlation spectroscopy data from live HeLa cells transfected with fluorescent-protein-tagged c-Fos indicated that c-Fos formed homodimers. We developed a method to determine the absolute concentrations of transfected and endogenous c-Fos and c-Jun, which allowed us to determine dissociation constants of c-Fos homodimers (Kd = 6.7 ? 1.7 ?M) and c-Fos?c-Jun heterodimers (on the order of 10 to 100 nM) from FRET titrations. Imaging fluorescence cross-correlation spectroscopy (SPIM-FCCS) and molecular dynamics modeling confirmed that c-Fos homodimers were stably associated and could bind to the chromatin. Our results establish c-Fos homodimers as a novel form of the AP-1 complex that may be an autonomous transcription factor in c-Fos-overexpressing tissues and could contribute to tumor development.
Tárgyszavak:	Természettudományok Biológiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban c-Fos homodimerization dissociation constant fluorescence correlation spectroscopy SPIM-FCCS FRET live cell imaging oncogene protein-protein interactions protein-DNA interactions
Megjelenés:	Molecular And Cellular Biology. - 35 : 21 (2015), p. 3785-3798. -
További szerzők:	Krieger, Jan Wolfgang Komáromi István (1957-) (vegyész, molekuláris biológus, biokémikus) Tóth Katalin (Heidelberg) Vámosi György (1967-) (biofizikus)
Pályázati támogatás:	K103965 OTKA TÁMOP-4.2.2.A-11/1/KONV-2012-0023 TÁMOP MÖB/21-1/2013 Egyéb TÁMOP-4.2.4.A/2- 11/1-2012-0001 TÁMOP
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001-es BibID:	BIBFORM065088
035-os BibID:	(Cikkazonosító)33022 (WOS)000382917700001 (Scopus)85047916061
Első szerző:	Vámosi György (biofizikus)
Cím:	EGFP oligomers as natural fluorescence and hydrodynamic standards / György Vámosi, Norbert Mücke, Gabriele Müller, Jan Wolfgang Krieger, Ute Curth, Jörg Langowski, Katalin Tóth
Dátum:	2016
ISSN:	2045-2322
Megjegyzések:	EGFP oligomers are convenient standards for experiments on fluorescent protein-taggedbiomolecules. In this study, we characterized their hydrodynamic and fluorescence properties.Diffusion coefficients D of EGFP1-4 were determined by analytical ultracentrifugation withfluorescence detection and by fluorescence correlation spectroscopy (FCS), yielding83.4?48.2 ?m2/s and 97.3?54.8 ?m2/s from monomer to tetramer. A "barrels standing in arow" model agreed best with the sedimentation data. Oligomerization red-shifted EGFPemission spectra without any shift in absorption. Fluorescence anisotropy increased,indicating homoFRET between the subunits. Fluorescence lifetime decreased only slightly(4%) indicating insignificant quenching by FRET to subunits in non-emitting states. FCSmeasuredD, particle number and molecular brightness depended on dark states and lightinducedprocesses in distinct subunits, resulting in a dependence on illumination powerdifferent for monomers and oligomers. Since subunits may be in "on" (bright) or "off" (dark)states, FCS-determined apparent brightness is not proportional to that of the monomer. Fromits dependence on the number of subunits, the probability of the "on" state for a subunit wasdetermined to 96% at pH8 and 77% at pH6.38, i.e., protonation increases the dark state. Thesefluorescence properties of EGFP oligomeric standards can assist interpreting results fromoligomerized EGFP fusion proteins of biological interest.
Tárgyszavak:	Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban folyóiratcikk oligo-EGFP FP photophysics diffusion coefficient molecular brightness protein oligomerization
Megjelenés:	Scientific Reports. - 6 (2016), p. 1-12. -
További szerzők:	Mücke, Norbert Müller, Gabriele Krieger, Jan Wolfgang Curth, Ute Langowski, Jörg Tóth Katalin (Heidelberg)
Internet cím:	Intézményi repozitóriumban (DEA) tárolt változat
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